1. Field of the Invention
The present invention relates to a pointing device.
2. Description of the Background Art
FIG. 1 is a plan view showing the appearance of a mouse 20 (available from Apple Computer Inc.), a conventional pointing device, and FIG. 2 is a cross sectional view of FIG. 1 taken on lines A--A'. The mouse 20 is of an appropriate size so that it fits to a palm when held in a hand, and is connected with a terminal unit (not shown) by a cable 6 for signal transmission. As shown in FIG. 2, to measure a distance the mouse 20 has moved, a mechanism 7 is attached to a bottom portion of the mouse 20. A ball 21 is mounted to the mechanism 7. Finding rotations of the ball 21, the mechanism mechanically detects the distance the mouse 20 has run. Alternately, the mouse 20 comprises an optical sensor which optically detects the distance the mouse 20 has moved on a checker-patterned pad.
A button 2 is attached to the mouse 20 in a position where it can be easily reached by fingers of a gripping hand. Mouses of this type with two or three buttons are also already available in the market.
Operation of the mouse 20 will now be explained. An operator puts the mouse 20 on a flat surface, for example on a desk, and holds the mouse 20 with a hand. By moving an arm, the operator moves the mouse 20 widthways and lengthways. The distance the mouse 20 has moved determines X coordinate and Y coordinate to be inputted to the terminal unit, according to which a cursor moves on a display screen connected with the terminal unit. Having confirmed a cursor position moved on the display, the operator clicks the button 2 to determine the X and the Y coordinates so that software running on the terminal unit or a host computer executes a command specified by the determined X, Y coordinates. A resulting operation differs depending on software.
With the structure as above, the mouse 20, a conventional pointing device, demands not only a space on a desk large enough to be moved around but also requires repeated movements of an arm to input a large displacement. Further, nothing but two dimensional data can be inputted since the mouse 20 is operated only on a plane.